Optical Properties Of Pr3+-, Ce3+-, And Eu2+- Doped Ternary Lead Halides

The luminescent properties of rare-earth doped solids have been under intense exploration for a wide range of applications ranging from displays and lasers to scintillators. In this work, the material purification, crystal growth, and spectroscopic properties of Ce3+-, and Eu3+- doped KPb2Cl5 as well as Pr3+ doped KPb2Cl5 and KPb2Br5 were investigated for possible applications in infrared lasers and radiation detectors. The studied materials were synthesized through careful purification of starting materials including multi-pass zone-refinement and halogination. The growth of the purified materials was then carried out through vertical or horizontal Bridgman technique. The trivalent praseodymium ion (Pr3+) offers a large number of laser transitions in the visible and infrared (IR) spectral regions. Using similar to 1.45 mu m and 1.9 mu m pumping, IR emissions at similar to 1.6, similar to 2.4, and similar to 4.6 mu m were observed from Pr: KPb2Cl5 and Pr: KPb2Br5 corresponding to the 4f-4f transitions of F-3(4)/F-3(3) -> H-3(4), F-3(2)/H-3(6) -> H-3(4), and H-3(5) -> H-3(4), respectively. Large emission cross-sections in the range of (4.8-6.1) x 10(-20) cm(2) (near-IR, similar to 1.6 mu m) and (5.5-6.0) x 10(-20) cm(2) (mid-IR, similar to 4.6 mu m) were observed for both crystals. Emission characteristics of the similar to 1.6 mu m Pr3+ transition including IR to visible upconversion emission studies were also discussed. Under Xenon lamp excitation, preliminary spectroscopic results showed allowed 5d-4f Ce3+ emission centered at similar to 375 nm in Ce3+ doped KPb2Cl5. In addition, commercial Ce:YAG and Ce:YAP crystals are included in this study for comparison. Pr3+ and Eu2+ 5d-4f emissions were not observed from Pr3+/Eu2+ doped KPb2Cl5 crystals.